What happened
On 12 March 2017, a Robinson R44 Clipper II, registration G-DORM, was performing a private flight from Derryogue airfield in Northern Ireland. The pilot's original plan was to fly toward Slieve Croob, but due to increasingly windy and uncomfortable weather conditions, the pilot decided to divert to a private landing site located at his residence near Carlingford, Co. Louth.
As the helicopter approached the landing site, the pilot encountered a sudden squall. During the landing sequence, the aircraft lost control, causing the main rotor blades to strike a public road. The helicopter subsequently impacted dense trees and shrubs in a neighbor's garden. The aircraft was destroyed, though no fire occurred. The pilot and one passenger both sustained serious injuries.
The investigation
AAIU investigators examined the wreckage and analyzed radar data from Dublin Air Traffic Control. The radar showed the aircraft climbing and maneuvering over Carling and Carlingford Lough before descending toward the landing site. Physical examination of the wreckage revealed extensive damage to the main rotor blades and the tail boom, including a fractured tail rotor drive shaft.
Investigators also reviewed the pilot's credentials, noting a valid FAA-issued license and medical certificate. The investigation also looked into the aircraft's maintenance history and safety features, noting that the implementation of a manufacturer's service bulletin regarding fuel tanks may have prevented a post-crash fire. Additionally, investigators found that a safety pin was still inserted in the landing skid float cylinder, which would have prevented deployment in an over-water emergency.
Findings
- The primary cause of the accident was the loss of control while attempting to land.
- The landing site was highly susceptible to adverse weather, specifically "rogue winds" and sudden squalls.
- Witnesses observed the helicopter swaying and spinning prior to the impact.
- A large collective lever input, potentially used to counter the sudden downward force of a squall, may have contributed to an accelerating yaw rate.
- The use of four-point restraint harnesses likely aided the survival of the two occupants.